The invention provides a device for enabling a load to be moved along a path defined by an elongate guide member, freely past support or attachment points for the guide member.
A load attachment system comprising a securely fastened guide line allows personnel or equipment to move along the general path of the elongate guide line whilst being attached thereto by means of a fastener engagable with the guide line for sliding movement therealong. If the fastener is in the form of a clip, it is necessary to detach the clip from the guide line at each immediate fixed location point along the length of the guide line and then re-engage the clip with the guide line on the other side of the location point. U.S. Pat. Nos. 4,265,179; 4,470,354 and 4,462,316, the disclosures of which are included herein by reference, describe traversing devices which can be located as a sliding fastener, e.g. at the end of a safety harness lanyard, for engagement with a guide line enabling passage past the intermediate location points of the guide line without detachment of the fastener from the guide line.
The object of the invention is to provide another form of load attachment, traversing device for use with an elongate element secured at positions spaced along its length with respect to a fixed structure. Such a system provides an alternative structure to those of the above-described prior art constructions which in some embodiments provide technical advantages, such as reduction of manufacturing precision required for some parts of the apparatus.
DE-OS-2,020,746 discloses a cable location station having mounted thereon spring-loaded rollers for locating a moving cable whilst permitting the passage of cable grips connecting the cable to a movable trolley structure which is constrained to move along a pair of fixed rails. This specification is not concerned with a load attachment device movable along and located solely by a fixed elongate track element such that, under load, the attachment device remains securely fastened to the track element whilst being able to traverse intermediate support positions of the track element.
U.S. Pat. No. 4,154,171 discloses an overhead cable transport installation utilizing a pair of pulley wheels which may separate against the action of a spring to permit the passage of cable grips therebetween. The cable is not entrapped by pulley wheels to prevent disengagement therefrom. Once again this specification is not concerned with a load-attachment device which is movable along and located solely by a fixed elongate track element such that, under load, the attachment device remains positively engaged with the track element which is trapped in a channel through the device.
U.S. Pat. No. 878,653 discloses a trolley pulley in which two rollers mounted above the support cable are spring-loaded to be movable upwardly to pass a cable grip or similar obstruction on the cable. However, under heaving loading the cooperating pulleys located below and above the cable tend to separate thereby allowing detachment from the cable.